224 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



5. A general, annular, prelamellar cavity is present in both 

 species. The ground tissue beneath the young annular hymeno- 

 phore zone lags behind the latter in growth and the tension 

 thus arising tears the ground tissue apart, forming a general 

 annular cavity into which the gill salients extend. It is distinct 

 in both species, but very large in L. seminuda in comparison with 

 the size of the basidiocarp. 



6. The blematogen ("universal veil" p. p. of Fries and other 

 writers) is prominent in both species, but more striking in Lepiota 

 seminuda than in L. cristata. In the latter species, in the young 

 stage, it consists of radiating, slender, more or less flexuous hyphae 

 over the pileus area, and of longitudinal hyphae parallel with the 

 stem axis, below the pileus area. As the pileus is organized and 

 becomes concrete with the blematogen, the latter over the pileus 

 and for a short distance below the pileus margin, becomes organ- 

 ized into a definite duplex layer, the outer zone consisting of a 

 compact palisade of cylindrical hyphae, the inner forming a thin 

 zone of small-celled pseudoparenchyma. With the expansion of 

 the pileus the blematogen layer over the pileus becomes torn into 

 more or less erect fibrous scales, giving the pileus a cristate appear- 

 ance. In Lepiota seminuda the radial hyphae forming the blema- 

 togen become transformed into chains of globose or subglobose 

 cells which easily fall apart, giving a mealy or powdery appearance 

 to the basidiocarps. The blematogen thus crumbles easily and 

 with slight friction may nearly all be rubbed ofT the pileus, leaving 

 only fragments of it attached to the pileus surface. But it does 

 not become separated from the pileus by a cleavage layer as the 

 volva of the Amanitae is, nor does complete desquamation take 

 place by the formation of a well-defined outer i)ilous layer as in 

 certain species of Copriniis. 



Bibliography 

 1906. Allen, C. L. The development of some species of Ilypholoma. 



Ann. Myc. 4: 387-394. pJ. 5-7. 1906. 

 1906. Atkinson, G. F. The development of Agaric us campestris. 



Bot. Gaz. 42: 241-264. p^7-i2. 1906. 

 1914. . The devclopmenwjf Agaricus arvensis and A. comtidiis. 



Am. Jour. Bot. i: 3-22. pi. J, 2. 1914. 

 1914. — ■ — — . The development of /I rw^V/ar/fl /;/(7/fa. Myc. Centralb. 



4: 113-121. pi. I, 2. 1914. 



